Chapter # 2 Spirometry Lecture Flashcards
Normal Values Usually come from:
They come from the statistical analysis of healty people
The physical characteristic that most influence pulmonary function include:
- Age
- Sex
- Height
- Race or ethnic
- Weight or body surface area
Why Ethnecy influence on laboratory reference values?
Because of people height.
Some groups of people are small or tallest than normal average. forthermore their measurements must be according to them stature.
Most clinical laboratories cosider two standar deviations from the mean as the normal rage and these include:
95% of the healthy people.
- Values bellow 2SD (95%), in the lower limit of normal is consider ABNORMAL.
- Values ABOVE 2SD (95%), in the lower limit is concider ABNORMAL as well. Both LLN are know as 5% percentile
When performing PFT’s 3 values are reported:
- Actual
- Predicted
- % Predicted
On PFT, the Actual Value is:
The Acual Value is what the patient performed
predicted Value on PFT is:
What the the patient should have performed base on Age, Height, Sex, Weight and Ethnicity
PFT % predicted is:
A comparison of actual value to the predicted value.
In clinical medicine the 5% percentile is often difined as:
The LLN, because it represents the segment of helthy subjects farthest bellow the average.
Vital Capacity (VC) is:
VC is the volume of gas measured from slow, complete expiration after a maximun inspiration, whithout effort.
Vital Capacity consist of what lung volumes?
VC consist of three lung volumes:
- IRV= Inpiratory reserve volume.
- Vt= Tidal Volume
- ERV= Expiratory reserve volume.
Lung capacity happen when:
we combine two or more lung volumes
How we calculate RV?
By Subtructing FRC-ERV
ex: RV = FRC-ERV
How we calculate TLC?
BY adding IC+FRC.
ex: TLC= IC + FRC
What are the VC Criteria for Acceptability?
- End-expiratory volume varies by less than 100ml for three preceding breaths.
- Volume Plateau observed at maximun inspiration and expiration
- Two acceptable VC maneuvers should be obtained within 150ml
- The largest value from at least 3 acceptabe maneuvers should be reported
What’s left in the lung after end expiration?
FRC
(Force Vital Cpacity)
What are the comparment of volumes of the lungs?
- IRV
- Vt
- ERV
- RV
On VC criteria for acceptbility, how many manuever we should obtained , within what number and which one we report?
We should obtained two acceptable manuever within 150ml, and we report the LARGEST one out of those two.
On VC criteria for acceptability End Expiratory Volume varies by how many ml?, preciding for how many breaths?
On this criteria EEV varies less than 100ml, for three precing breaths.
On VC criteria for acceptability, when we have an acceptable plateau manuever?
Here we have an acceptable manuever when Plateau line picks and levels off. then we have an acceptable mauever.
What Pathology condition can decrease Lung Volume?
Any condition that causes lost of Lung Volume like:
- Lung Cancer
- Pulmonary Edema
- pulmonary Vascular Congestion
- Pneumonia
- Atelectasis
Why Obstructive Lung Disease can cause decrease VC?
Because of the gas trapping, resulting in elevated RV but normal TLC
What does it mean Reduced Chest Wall Excursion? and what condition causes?
Reduced Chest Wall Excursion means that the chest can NOT open mormally as a consecuense reduce Lung Volume or VC.
- Neuromuscular weakness
- Chest Wasll Deformity
- Obesity
- Pregnancy
- pain. All these contition will decrease VC
If Vital Capacity is less than 80% means?
Arway Obstruction